LiNbO₃ High Order Lamb Wave Resonators with Composite Plate Structure

The paper demonstrates the design and analysis of high-order asymmetric (A) and symmetric (S) resonators with the structure of Z-cut Lithium Niobate (LiNbO₃) thin film and silicon oxide (SiO₂) layer. This structure can enable high frequency of more than 3.5 GHz of high-order A mode and S mode. It can also achieve high electromechanical coupling coefficient (kt2) of 22.1% in S² mode and 17.1% of A3 mode by setting the thickness ratio of LiNbO₃ thin film and SiO₂ layer in theory. Such a high coupling coefficient enables the large bandwidth of acoustic-based RF filters.